Within the industry for the manufacture of timber houses, e.g. prefabricated houses, and houses constructed from both wood and other materials, it is of major importance to be able to assemble structures, e.g. roof trusses, in as rapid and rational a manner as possible without jeopardising accuracy and reliability. It is further of importance that the positioning of the timber lengths which are included in the structure and which are cut and otherwise treated beforehand may be carried out rapidly and simply without any major risk of incorrect positioning. The laid-out timber lengths are fixed provisionally to one another by means of, for example, corrugated fasteners with the aid of a nail pistol or the like in order to make possible movement of the structure for the final fixing together of the timber lengths to one another at each joint by means of so-called corrugated fasteners which can be adapted to the different joints between the timber lengths. Thus, there is a major need in the art for an apparatus for rational handling of the corrugated fasteners and pressing of the correct corrugated fastener over the joint intended therefore. In recent years, it has proved that there is a further need for automation of the assembly procedure or interconnection (the nailing operation) of roof trusses. It is further desirable to be able rapidly and automatically to adapt equipment to suit different types of roof trusses. This implies that it is desirable to reduce and preferably eliminate the necessary downtimes or waiting times.